Rats with either bilateral electrolytic or sham lesions of the ventrolateral portion of the lateral parabrachial nucleus (VLLPBN) were implanted with latex balloons that lay at the right superior vena cava/atrial junction (RSVC/AJ). Water intake in response to isoproterenol was measured both with and without inflation of the balloon. Water intake of the sham-lesioned rats was significantly depressed by balloon inflation during the first hour of the experiment. In contrast, water intake in the VLLPBN-lesioned rats was unaffected by balloon inflation. These results suggest that the VLLPBN is involved in the processing of afferent input from stretch-activated RSVC/AJ receptors.